The present invention provides the hearing aids that can all be placed in the ear and has the following features: cosmetic hiding ability, and always maintain elastic contact with the ear canal, which can be placed closer to the human eardrum, comfortable to wear and stability, can be wear for long time, effectively reduce the feedback and the occlusion effect, clear sound transmission, reduce the device delivered gain loss. This hearing device is suitable for mild to severe hearing-impaired patients. Because this device can be bendable to comply with each individual ear canal curve and then comfortably sit inside the ear cannel so there is no need to take the ear impression to greatly reduce the hearing aid fitting process and time.